Bug 1039162 - Don't use |for each| in XPCOMUtils.jsm. r=mrbkap.

|for ... each| loops create an Iterator object each time they execute. They're
also an E4X hangover. Converting them to vanilla arrays avoids the creation of
almost 6,000 Iterator objects when starting up B2G, mostly due to makeQI().

--HG--
extra : rebase_source : f3a3fe2d64a045dacf70461611d9a0b72a38a210